550
ACUS01 KWNS 050537
SWODY1
SPC AC 050536
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT TUE MAY 05 2026
VALID 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTERED OVER
ARKANSAS AND EXTENDING FROM NORTHEAST TEXAS INTO WESTERN
TENNESSEE...
..SUMMARY
WIDELY SCATTERED SEVERE STORMS ARE POSSIBLE TUESDAY AFTERNOON INTO
TUESDAY NIGHT FROM NORTHEAST TEXAS INTO WESTERN TENNESSEE, WITH THE
MAIN THREAT CENTERED OVER ARKANSAS. THE STRONGEST STORMS WILL BE
CAPABLE OF LARGE HAIL, DAMAGING WINDS, AND A FEW TORNADOES. MORE
ISOLATED, STRONG TO SEVERE STORMS ARE POSSIBLE ACROSS PARTS OF THE
NORTHEAST.
..SYNOPSIS
A VIGOROUS, MID-LEVEL LOW OVER ONTARIO THIS EVENING IS FORECAST TO
EVOLVE INTO AN OPEN WAVE WHILE TRANSLATING EAST INTO QUEBEC ON
TUESDAY. AN ACCOMPANYING BELT OF STRONG, MID/UPPER-LEVEL WINDS WILL
OVERSPREAD THE LOWER GREAT LAKES AND NORTHERN NEW ENGLAND IN TANDEM
WITH MODEST HEIGHT FALLS RELATED TO A VORTICITY MAXIMUM PIVOTING
THROUGH THE BASE OF THE PARENT SYSTEM. ELSEWHERE, A MID-LEVEL LOW
CURRENTLY ALONG THE CA COAST IS EXPECTED TO WEAKEN WHILE SHIFTING
THROUGH THE LOWER-CO VALLEY TO THE VICINITY OF THE FOUR CORNERS
REGION. A BELT OF 50-70 KT WINDS AT 500 MB ARE FORECAST DOWNSTREAM
FROM THAT FEATURE, EXTENDING FROM THE SOUTHERN PLAINS INTO THE MID
SOUTH ON TUESDAY AFTERNOON INTO EVENING.
IN THE LOW LEVELS, A COLD FRONT IS EXPECTED TO EXTEND FROM SOUTHEAST
QUEBEC THROUGH THE OH AND MID-MS VALLEYS TO LOW PRESSURE OVER OK
TUESDAY MORNING. THE NORTHERN EXTENSION OF THE BOUNDARY WILL MOVE
INTO THE LOWER GREAT LAKES AND NORTHERN NEW ENGLAND DURING THE PEAK
OF THE DIURNAL HEATING CYCLE. THE SEGMENT OF THE FRONT ACROSS THE
OZARKS AND OZARK PLATEAU MAY BE TEMPORARILY DISPLACED TO THE SOUTH
TUESDAY MORNING DUE TO OVERNIGHT THUNDERSTORM ACTIVITY. HOWEVER BY
AFTERNOON, THE FRONT IS EXPECTED TO REFOCUS IN THE VICINITY OF THE
MO-AR BORDER, AHEAD OF A WEAKENING SURFACE LOW MOVING THROUGH
EASTERN OK INTO WESTERN AR. THE WESTERN EXTENSION OF THE COLD FRONT
TRAILING THE SURFACE LOW IS EXPECTED TO ADVANCE SOUTHEAST THROUGH
THE RED RIVER VALLEY.
...NORTHEAST TEXAS INTO THE SOUTHERN MISSOURI AND WESTERN
TENNESSEE...
AS MENTIONED IN THE SYNOPSIS, A COMPLEX OF THUNDERSTORMS MAY BE
ONGOING AT THE START OF THE FORECAST PERIOD ACROSS PORTIONS OF MO
INTO NORTHERN AR. THAT ACTIVITY IS EXPECTED TO SHIFT EAST OF THE
AREA BY LATE MORNING OR EARLY AFTERNOON, WITH SOME LINGERING SHOWER
AND THUNDERSTORM DEVELOPMENT OCCURRING TO THE NORTH OF THE FRONT IN
CENTRAL MO. IN THE WAKE OF THE EARLY-DAY CONVECTION, HREF CLOUD
FORECASTS INDICATE THE POTENTIAL FOR CONSIDERABLE HIGH-LEVEL CLOUDS
AND POCKETS OF THICKER LOW-CLOUDINESS, WHICH COULD LIMIT THE
POTENTIAL FOR STRONGER DIABATIC WARMING WITHIN THE PRE-FRONTAL AIR
MASS. NONETHELESS, THE PRESENCE OF BOUNDARY-LAYER DEWPOINTS IN THE
60S IN CONJUNCTION WITH AN ELEVATED-MIXED LAYER (EML) PLUME WILL
SUPPORT A MODERATELY UNSTABLE AIR MASS BY AFTERNOON WITH MLCAPE OF
1000-2000 J/KG.
NEUTRAL TO SLIGHT HEIGHT RISES ARE FORECAST IN THE MID LEVELS DURING
THE PEAK OF THE DIURNAL HEATING CYCLE WITH MODEL FORECAST SOUNDINGS
INDICATING CONSIDERABLE CAPPING AT THE BASE OF THE EML. AS SUCH,
EVENTUAL STORM COVERAGE REMAINS UNCERTAIN. THE 00Z HIGH-RESOLUTION
MODELS SUGGEST THAT ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL
BECOME INCREASINGLY LIKELY BY LATE AFTERNOON OR EARLY EVENING ALONG
THE FRONTAL SEGMENT ALONG THE MO-AR BORDER, IMMEDIATELY
EAST/NORTHEAST OF THE SURFACE LOW. ADDITIONAL, ISOLATED STORM
DEVELOPMENT ALSO APPEARS POSSIBLE FROM THE VICINITY OF THE SURFACE
LOW SOUTHWEST ALONG THE COLD FRONT INTO NORTHEAST TX, MAINLY DURING
THE EVENING HOURS.
THE FAVORABLE OVERLAP OF MODERATE INSTABILITY AND STRONG DEEP-LAYER
SHEAR WILL FAVOR SUPERCELL STORM MODES, ESPECIALLY GIVEN THE
ANTICIPATED WEAK FORCING FOR ASCENT. LARGE HAIL WILL BE THE
PREDOMINANT SEVERE-WEATHER HAZARD INITIALLY. A FEW TORNADOES APPEAR
POSSIBLE ACROSS PORTIONS OF NORTHERN AR, POTENTIALLY INTO WESTERN TN
FROM LATE AFTERNOON THROUGH THE EVENING ASSOCIATION WITH ANY
SUSTAINED SUPERCELLS. HERE, THE PRESENCE OF A 35-40 KT LOW-LEVEL JET
WILL YIELD EFFECTIVE SRH OF 200-300 M2/S2 AMIDST A MOIST/LOW-LCL
ENVIRONMENT. STORMS MAY EVENTUALLY GROW UPSCALE INTO CLUSTERS, AT
WHICH POINT DAMAGING WINDS WOULD BECOME A GROWING CONCERN.
..LOWER GREAT LAKES INTO NORTHERN NEW ENGLAND
MOISTURE ADVECTION OCCURRING ALONG A SOUTHWESTERLY LOW-LEVEL JET
WILL ALLOW DEWPOINTS TO RISE INTO THE 50S WITHIN THE PRE-FRONTAL
WARM SECTOR ON TUESDAY. AND WHILE MID-LEVEL LAPSE RATES ARE NOT
EXPECTED TO BE PARTICULARLY STEEP, THE MOISTURE INCREASE COMBINED
WITH DAYTIME HEATING AND THE RESULTANT STEEPENING OF LOW-LEVEL LAPSE
RATES WILL RESULT IN MLCAPE OF 500 TO PERHAPS 1000 J/KG. INCREASING
HEIGHT FALLS ALOFT AND CONVERGENCE/LIFT ALONG THE COLD FRONT ARE
EXPECTED TO SUPPORT SURFACE-BASED STORM DEVELOPMENT BY EARLY
AFTERNOON WITHIN THE DESTABILIZING AIR MASS ACROSS PORTIONS OF
UPSTATE NY. THE STORMS WILL QUICKLY OVERSPREAD NORTHERN PORTIONS OF
VT, NH, AND ME DURING THE AFTERNOON INTO EARLY EVENING.
THE 00Z HIGH-RESOLUTION MODELS INDICATE THE POTENTIAL FOR TRANSIENT
SUPERCELL AND BOWING STRUCTURES, WHICH APPEARS REASONABLE GIVEN THE
PRESENCE OF A RELATIVELY STRONG, DEEP-LAYER WIND FIELD. IN THAT
SCENARIO, ISOLATED OCCURRENCES OF DAMAGING WINDS AND PERHAPS SOME
MARGINALLY SEVERE HAIL APPEAR POSSIBLE. THE TORNADO THREAT WILL BE
CONDITIONAL ON SUFFICIENT INSTABILITY TO SUPPORT MORE SUSTAINED
SUPERCELL STRUCTURES. A LEVEL 1/MARGINAL RISK WILL BE MAINTAINED;
HOWEVER, IF IT BECOMES APPARENT THAT STRONGER INSTABILITY WILL
DEVELOP THAN IS CURRENTLY ANTICIPATED, AN UPGRADED TO LEVEL 2/SLIGHT
RISK MAY BECOME NECESSARY.
..MEAD/LYONS.. 05/05/2026
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